To a flask was added 4-(2,4-bis(trifluoromethyl)benzyloxy)-3-methoxybenzaldehyde from Step A (164 mg, 433 μmol), rhodanine (58 mg, 433 μmol), absolute EtOH (7 mL), and TEA (120 μL, 870 μmol). The reaction solution was allowed to stir at 65° C. for 14 h. The reaction solution was diluted with EtOAc (100 mL), washed with sat. NH4Cl (75 mL×3), dried over Na2SO4, filtered, and concentrated to ⅓ the original volume. The yellow precipitates were isolated by filtration under reduced pressure, washed with EtOAc (50 mL) and Et2O (50 mL) to afford the title compound (47 mg, 23%). 1H NMR (DMSO-d6) δ 13.25 (1H, br s), 7.90 (1H, d, J=8.1 Hz), 7.86 (1H, s), 7.80 (1H, d, J=8.60 Hz), 7.48 (1H, s), 6.99 (1H, dd, J=2.0 Hz, 8.6 Hz), 6.96 (1H, d, J=2.0 Hz), 6.86 (1H, d, J=8.3 Hz), 5.35 (2H, s), 3.88 (3H, s); MS (ESI) 494 (MH+).
